Spark-plug tester.



warmere s. wlrfrnn, or TOLEDO, IOWA.

SPARK-PLUG TESTER.

Specification of Letters Patent.

lPatenteol May 23, 1916.

Application inea november ae, 1914. sei-iai neef/4,567.

` To LZZ 'whom 'may concern.'

Be it known that l, WILLIAMS. VVrr'rEii, a' citizen of the United States, residing at lToledo, in the county of Tama and State of Iowa, have invented certain new and useful Improvements in Spark-Plug Testers, of which the following is a specification, refi erence being had tothe accompanying drawings.

t/ly invention relates to means for testing spark plugs, and particularly to a device which is so constructed that it may he readily applied to the spark plug to be tested, and will show whether the spark plug is in good Working order by permitting a spark to pass between .the electrodes of the tester.

The main object of my invention is the provision of a very simple, easily handled and eiiective testerwherein a single conduc- .spark juin tor is used for the purpose of conducting the current from the'one terminal of the spark plug 'to-the electrodes disposed within the tester, no return circuitbeing used or necessary. Y n i a A further object of the invention is to provide a spa'rkplug tester wherein the elec trodes'of'f`the tester are inclosed within an yopaque tubeofnonconducting material and wherein a magnifying glass is so disposed that when the tube is held to the eye the i i ping between the electrodes will be plainly visible.

A rfurther object of the Vinvention isy the provision of a testerso constructed that a flexibleJ conductor is providei'l normally contained within the tester, but adapted to be ywithdraw-n therefrom and applied to the spark plug while the ,tester itself is held in .such position that its spark may be readily observable.

A further'object is to provide means in a tester whereby the length `of the testing spark may be adjusted by adjusting the distance between the electrodes.

Further objects will appear the course of the following description.

lily invention is illustrated iny the accompanying drawings, wherein-4,

Figure 1 is a longitudinal' diametiical section of a spark plug tester constructed in accordance .with my invention.; Fig. 2 is a section on the line 2-2 of Fig. 1; Fig/3 is a Section on the line 3 3 of Fig. 1.

Corresponding and like paiftsiare referred vto in the following description and designated in all parts of the accompanying drawings by like referencenumerals.

Referring to thesefigures, 2 designates a tubular insulating shell, which maybe made of hard rubber, vulcanized fibel', or any other insulating material. The shell is open at both ends. Disposed within the shell, at about its middle, is an interior'sleeve 3 of iron or other suitable metal. This shell 3 is tubu ar in form and has a assage 4 eX- tending through its'center, this passage tapering toward one end so as to provide a shoulder 5. leyoiid this shoulder the passage is annularly enlarged as at 6, and beyond this enlargement the passage is again annularly enlarged as at 7, thus providing a shoulder 8. Disposed against one end of the sleeve and resting thereon is a niagnifying lens 9 which is held in place by a sleeve 10 of metal or any other suitable material. Disposed within the annular space' and forced against the shoulder 5 is an annular electrode 11, the central opening of which is eccentric to the exterior diameter. Disposed within the annular enlargement 7 of the bearing or sleeve 3 is a plug 12 of insulating material. This plug is cemented in place within the sleeve 3, and passing through the plug is Athe screw pin 13, the inner extremity of which-carriesthe electrode pin 14. This pin 1&1 is disposed eccentrically to the airis of the screw pin 13, soy that as the screw pin is turned, the electrode pin 14- may be brought nearer to 0r farther from the wall of the central openingr in the annular electrode 11. The screw pin 13 is provided with a head' 15 around which fits a shackle ring 1G having an eye to which is connected a chain 17. This chain may be of any suitable length and is normally contained within a chamber 18 formed by the unoccupied hollow end of the insulating tube 2. The extremity of the chain-17 has attached to it a shackle ring 19 connected with a 'swivel 2O carrying a ring 21. This swivel is operatively engaged with a metal cap 22 having a diameter approximately equal to that of the tubular body 2 and having an intei'iorly extending flange 23 litting snugly within the tube 2, so that when this cap is in place it will he held by frictional engagement with the walls of the insulating tu e.

vThe operation of my inventionis as foli lows: The lens 9 is not only for the purpose lin use, but also acts to prevent the entrance of dust into the bore 4 and onto the eleclll) trodes. It is of course obvious that dust cannot enter through the plug 12, inasmuch as the bore of this plug is always tightly closed by the screw pin 1S., In use the cap 22 is removed from the end of the tube. and the ring 21 is placed on top of the spark plug. If a spark jumps between the electrodes of the spank plug a small spark will pass between the electrodes 11 and 11 which will be plainly seen through the magnifying glass 9. It will be understood that this qtester works with a high voltage current which is obtained through an induction coil, and I have found in practical experience with my tester that when the ring 21 is placed on top of the spark plug a small spark will jump across from electrode 11 to electrode 14 when the primary circuit of the induction coil is broken. Because of the fact that this is used on a secondary circuit with a high tension current, the current' will iow into the electrode 11 and the currentA will jump across the gap to the electrode 14. The magnifying. glass 9, it will be noted, is disposed inward of the adjacent end of the insulating tube 2, and the end of this tube is rounded as at 2i, thereby permitting the tube to be appliedto the eye so that an observer may look into a dark chamber and thus permit the spark to be plainlyV visible. It will be plain that my device is extremely convenient for use because of the fact that the flexible conductorl'? permits the instrument to be applied to the eye while-thc contact 21 is held against the spark plug. |This eliminates the necessity of holding' the implement itself in position against the spark plug and having to cramp the body at considerable personal inconvenience in order to observe the spark. By the use of my device vthe operator can stand upright and hold the tube 2 in any convenient position to the eye While holding the contact 21 against the spark plug with one hand. It also permits the device to be used where the spark plugs are difficult of access.

Because of the peculiar construction of my i testerand the fact that it has no return con-v ductor the spark which will -jump between the electrodes will be extremely small and would be very vdifficult to observe with the naked eye, particularly if the electrodes were not contained in a dark chamber. It is for this reason that it is necessary to provide a tube or casing wherein the electrodes are suppolted, this casing being opaque, and it is for this reason that it is necessary to provide in my construction a magnifying glass whereby the spark between the electrodes may be observed.

I am aware that spark plug testers have been provided in which one of the electrodes is adapted to be connected by a conductor to a spark plug` and the other electrede connected to a ground either through a return wire or conductor or through the body of the operator,'but constructions of this character are open to the objection that inasmuch as a complete circuit is provided the plug will short circuit more or less so that the plug will not give a full spark. A

complete circuit using two conductors, as

' and the other part through the tester. In

my tester I have no short circuit or appreciable return and therefore get the full spark the plug is giving at the time tested. While a very small spark is displayed in the tester, yet by means of the connections stated and by using the magnifying glass this spark is entirely evident to the operator.

My device is extremely .convenient for testingl spark plugs, but itmay also be used in a large number of other situations where it is desired to test the etiieiency of secondary circuits.

It will be seen that this tester is very com pact, and portable, and that, the parts being contained entirely within the tubular shell 2,

are housed and protected from damage or dirt. If the lens 9 should, .at any time, become damaged, it may readily be removed.

Having described my invention, what I claim is:

1. A spark plug tester comprising a support of insulating material, coacting spaced electrodes carried by the support and insulated thereby and a single conductor connected to a single one of said electrodes.

2. In a spark plug tester ofthe character described, an insulating supporting body, spaced electrodes mounted therein, a flexible metallic conductor attached to one of said electrodes and having means at its end whereby it may be electrically engaged With the spark plug, the other of said electrodes being insulated by said shell.

3. In a spark plug` tester of the character described, an insulating shell; a metallic sleeve disposed within the shell, an annularY 4. In a spark plug tester of the character described, a hollow shell of insulating material, a metallic sleeve disposed within the shell intermediate the ends thereof, a lens mounted upon one end of said sleeve, ,an

annular electrode adjacent the other end of the sleeve, an insulating plug ldisposed. in

iso

the last named end of; thesleeve-,an electrode carried thereby 'and coactingwith the first vvnamed electrode, 'fa detachable cap' closing the lastv namedV end ofthe tubular body, and a chain attached 'to the-last named electrode` and to the cap and having a greater length than the distance between the electrode and the cap and 'normally' contained in the hollow body.A

'5. In' a spark plug tester of the character i described, a tubular bodyof non-conducting material, a metallic sleeve disposed within the, body intermediate its ends, a magnifying lens supported at one end of the sleeve, a coacting electrode supported'in the other l end of the sleeve in spaced relation to the first named. electrode, a cap closing the end of the body opposite the magnifying lens, and a flexible conductor between said last named electrode and said cap, said connection being normally contained within the hollow end of the body.

6. In a spark plug tester of the character described, a tubular body of insulating material, a metallic sleeve disposed within' the body intermediate its ends and having a bore tapering toward one end, the bore then being enlarged, a magnifying lens disposed against the end 'of the sleeve at the large end of the bore, means for holding the lens in place, an annular electrode disposed within the sleeve at the small end of the tapered bore, applug of insulating material disposed in the enlargement of said bore, a rotatable pin carried in said plug and hava ing an eccentrically disposed electrode pin extending therefrom and coacting with the rst named electrode, a cap detachably closing the end of the body opposite the magnifying glass and carrying a member adapted to be applied to a spark plug, and a flexible metallic conductor disposed be.-

' tween said' pin and said cap.l Y

7. In aspark plug tester of the character described, an insulating shell, an electrode carried within the shell, an electrode also said "eXible connection' having a' length greater thanV the ldistance betv'veen the electrodes andthe adjacent endof the shell and a cap detachable fr'olnithat' ndof-thexbody throughlflwhich vthe adapted' to' .proie trodes, one offjsaidelectrodes being. annular' y in form, ,thel other of y said elctrodes comj",

disposed thereon andthe eccentric to the prising a pin having an electrode proper- 1 axis of the pin, the axis of the first electrode being disposed eccentrically to the axis of said pin.

9. In a spark plug tester of the character'-l described, a shell of insulating material, an

annularv electrode disposed within the shell, a non-conducting plug disposed within'the` shell, an electrode disposed Within the plug.-v

and vcarried 1n spaced'relation to the first named electrode, and means whereby the second named electrode may be connectedto a spark plug.

. 10. In a spar body of insulating material, an electrode k plugl tester, a supporting disposed within. the body and insulated thereby, an electrode also carried by the body coacting with but spaced from the first j electrode and means whereby the second named electrode alone may be electrically v connected to a spark plug.

11'. A spark plug tester including a supporting body of insulating material, coact-A ing insulated electrodes Acarried thereby and spaced'from each other, and a single :con-

ductor extending from and electrically con" nected to one of said electrodes alone and adapted to be connected in electrical engagement with a spark plug.

12. In a spark plugtester, a supporting body of insulating material, coacting in-' sulated electrodes carried thereby and.' 4spaced from each other, an electrical conductor connected to and extending from a f single one of said electrodes, the other electrode being entirely insulated from elec# trical connection with a ground.

13. In a spark plug tester, a supporting`v body of insulating material, an electrode carried thereby, means whereby thev 'elec- A l trode maybe electrically connectedtfofa spark plug and an electrically conductive 'body carried by the support/in "body and' :insulatedthereby from. grouri IVA1ng,"' hav1ng a relatively large electricalcapacity' and c0- vacting ,wilt -v and spaced from said firstnamed electrode.' Y

14. A spark plug vlow body, coacting insulated spacedelec- -trodes carried therein and "a flexible conf-. ductor 'connected to One'of' said velectrodes Zlio `tester, 4 includingla hol-I i I and' 'having on its extremity a capn'adal tied said' conductor is 'electricallyeennectedl In-,testimonyyhereof I hereunto afiiX my lsigna-ture in the presence' of witnesses. f '1 WILLIAM WITTER-f- Vlllitnessefs-: j

L. 1B,A Bmai G, M.. FER.

to close'one end 'of the hollc'ivy bqdyanj :in p. cluding a metallic' 'member gtogwhjch the 5' 

